Detector for locating gallstones and other hard foreign matter embedded adjacent body tissue



Nov. 4, 1952 c. K. KIRBY ETAI. 2,616,415

DETECTOR FOR LOCATING GLLSTONES AND OTHER HARD FOREIGN MATTER EMBEDDED ADJACENT BODY TISSUE Filed Feb. 15, 195o ll//A Arrow/viv Patented Nov. 4, 1952 vUNITE-D STAT-FES PitfIrE'Nfl OliFfIClI i' 'DETECTOR Fou` Looser-ING V"1G"A{L'Lsrro1\iEs lANDoTHER HARD FOREIGN MATTER BEBDEDADJACENT BODY TISSUE 'Charles "K; SKirby, Philadelphia, and 'jEdward"G.

Thurston and Eric AIWalkeryState College, Pa.

1 Application Februaryv 15, 1950, ZSerial`No..-f144,244

' OurV invention relates` @broadly -to rdiagnostic .apparatus .for use -by `physicians and surgeons, `.and more particularly ...an-electronic apparatus v.for locati-ng gallstones. and other hardfsubstances embedded adiacente-body tissues.

r.Olne of the otherobjectsof -our invention-is Yto V.prin/ide aA diagnostic apparatus v.-for use by physicians and-surgeons in `detecting gallstones in a patient withmini-mumrecourse to surgery.

' "Another .object -of-*our invention is kto' :provide ya compact-consta'uction Tofy .gallstones 1detector .in

vwhichY differences yinthe.characteristics of gall- :stones .and .adjacent body=tissu-e vmay be .made

audibly .apparent through` anar-:ous-tic system for .facilitating .diagnostic investigations of tl-1e :con-

dition of-a patient. I

Altoccoiiiditions. determined bythe movement. of a probe whereby the =-electron tube.y amplifica-tion system. ,provided- With-circuit. means tunedfto :pass audio irequenciesldisplaced from lthe frequency spectrum Yfrom vany .audio reso-nance trequency .present ...inthe probe structure for .rendering the` system sensitive to .frequencies .gener- .ated by ycontacto'f the. probewith gallstones uadjacent the'body tissue .beingdiagnosed .Anotherobject of our invention is toV provide a4 construction ofy probe for a `gullstone ,detector which. includes an .electroacoustical generator operative to developpotentials .under conditions of contact of the probe With gallstones wherethe probe is highly .damped and where the generator operates intoan Yelectron tube. amplifier system that is peaked to .respond to .frequencies generated incident toV contact of. saidprobe withgall- 1 stones-.as distinguished @from adjacent body. .tissuer for audibly .operating an v.electrical .acoustic system. Y

'Other and turtherob'jects of our. invent-lionne- 'side ther constructionY of probe .ifor agallstone detector as setforthv more fullyA in the speciiica- 'tionhereinafter .followingfby reference tothe accompanying drawings, in which:

Figure 1v is a longitudinal sectional .view through-.a `probe constructed. in; accordance with f2 #our invention; Fig. 2 is a vertical sectional View taken on line-2 2 of Fig. l.; andFig. 3 is aschematicand-vdiagrammatic circuit vdiagram showing .the electricalcircuit'of the electron tube amplication system Iand electrical sound .reproducer Yassociated with the probe of our invention.

The need for locating -gal-lstones Withminimum lsurgery will be .understood from considerations ot-thefdelicate- `formation of the .biliary tract .wherein the bile ductsvare small tubular structures .which-conveybile -from the yliver to the intestine. The rightand left hepatic 'ducts which drain the right and left lobes of the liverjoin to vform lthe common-.hepatic duct 'Wh-ich,A in turn, is .ioined by lthe cystic Aduct .from the gallbladder to lform the common `bile duct. After joining with the v.pancreatic duct, lthe common bile-duct .termina-tes in a small Asphincterfor circular mus- -c le,in thel wall of theintestine y The sphincter .allowsfbile y-toiiOw linto the intestine but effec- .tively seals the duct-against reverse flow.

.Gallstcnes -formin the .gall Abladder (rarely the bile ducts) and may pass through the bile ducts into -the Iintestine if they are --small enough vvtogo through-the sphincter. If. not,fthey are arrested at ther sphincter and block the flow of bile into the intestine.

lUsual-ly the Aobstructing stones lcannot be seen or-'tel-t, present-methods vof vdetecting them are citen ina-decuate.v The most effective method Vconsists of repeatedly .passing -a grasping Vforceps upland. down-the ducts, removing the stonesfas they are encountered. Passage' of instruments and cathetersthrough the sphincter into the intestine: is regarded Yas strong evidence that `the .obstruction has .been relieved but does not-dem onstrate` that all stones adjacent to the sphincter lor-in .the proximal ductshave `been r`removed. Theuse of X-rays, taken during operation with a ,radiO-'Opaquefdye .injected into the ducts, .Ilias ,been suggested but-not widely used. y

An equally .important problem is whether to open the=common bile `duct to explore fons-tones during operations-for-removal of the .gall -bladder. V.fin many instances the presence-'or absence oistones infthe bile ducts cannot be determined in anyiotherway. Opening of-:the-commonsbile duct-is undesirable if unnecessary. `1lhe instrument. of our invention yWhich-can be f passed through thecyst'icductupon removal of vthe/ gall .bladder to `detect. the .presence of. stonesin l, the bile duct, is,. therefore, of ,considerable value. "The detection r-instrument o 'four inventionexplores 4theshock waveproduced when a metal probe encounters a sall'stone; The detector employs an electroacoustic transducer using piezoelectric-crystal elements mounted at the back end of a slim rod-like probe and connected through an amplifier to a loudspeaker.

We have found that characteristic signals are produced whenever the sensitive probe comes into contact with a stone. The audible signal which consists either of a clicking noise when the probe is tapped against the hard surface of a stone, or of a scratching noise when the probe is scraped against a stone, is easily distinguished from a soft hissing produced when the probe is slid against tissues.

If the probe is undamped a ringing sound will result and can be produced by almost any slight shock, including impact with even relatively soft bodies. If the probe is highly damped a sharp click results and can usually be created only by striking the probe with a hard object. This latter effect is the one most desirable to achieve in the detector of our invention. The natural damping produced by the walls of the ducts helps to create such an effect, and audio resonances are further suppressed by a tuned circuit in the amplier, tuned to pass audio frequencies but displacedvfrom any audio resonance frequency presentin the probe structure.

The transducer is mounted at the back end ofv the probe inside the probe handle. The construction hasbeen found to provide a more sensitive transducer which is inexpensive to produce and which is entirely practical for production on a mass scale.

Referring to the drawings in detail the probe as shown in Figs. 1 and 2 comprises an electroacoustical generator I which is sensitive to mechanical displacement and minute pressure, for

Vgenerating electrical potentials. We may employ for this purpose any one of several sensitive elements such as a stack of ceramic piezoelectric elements soldered together in series. This material is available in sheets mils thick, and is quite rugged, and is capable of withstanding temperatures up to 117 C. As indicated by reference character I, we form a sensitive element by soldering together fourteen of these sheets to produce a packet 0.1875 by 0.25 by 1.5 inches. While fourteen of these sheets are shown in the form of our invention illustrated it is to be understood that we have specified fourteen for purposes of explaining our invention and we intend no limitations Ywith regard to the number of sheets. It is suilicient to point out that a multiplicity of said sheets are stacked to form a sensitive body that is substantially in the shape of a parallelopiped. The lcross section of the body is not square, but rectangular, one transverse side being longer than the other. The stacked body has an end portion Ial which is fastened to the circular conductive face of a header 2. The header 2 is a metallic cylindrical plug which is externally screw-threaded as represented at 2a for Vreceiving internal screw threads 3a formed on the end of the cylindrical metallic housing 3. The opposite end of housing 3 is also provided with internal screw threads 3b which engage external screw threads on cylindrical metallic 'header 4 closing the opposite end of the housing. The cylindrical metallic header 4 is provided With'an axially extending passage 5 therein through which a pair of electrical conductors 6a and 6b extend in a flexible casing of insulation material indicated at 6. The electrical conductors 6a and 6b in flexible casing 6 are fannedout interiorly of housing 3 and connect to electrodes 'I and 8 which are the electrodes for the electroacoustical generator I as shown more clearly in Fig. 2. These electrodes are applied to the longer side of the packet or parallelopiped constituting the electroacoustical generator I, thereby allowing adequate space for the passage of the ends of the yconductors 6a and 5b around the sides of the packet.

The packet or parallelopiped I is damped in its operation by contact at its peripheral edges with the interior wall of an insulation sheath 40 that is set into the interior of the metallic wall of housing 3, as represented more clearly in Fig. 2. The headers at each end of housing 3 are sealed with respect to housing 3 against entry of moisture by means of gaskets 9 and IIJ which are set in grooves in headers 2 and 4, respectively, and which establish an internal seal with the interior surface of housing 3. In the case of cylindrical header 4 the gasket I8 sets in both an annular groove in header 4 and in an internal groove interiorly of housing 3. The header 4 includes a ange portion II which abuts against the end of housing 3. An integral projecting portion I2 on header 4 is externally screwthreaded to receive the internally screw-threaded sleeve I4 of the metallic cap I5 which surrounds the electrical conductors 6. The metallic cap I5 compresses gasket IB within an annular recess formed in the end of projecting portion I2 of header 4 for establishing a huid-tight entrance for the electrical conductors 6a and 6b.

The connection between the end portion Ia of packet I and the conductive face of header 2 is made through a layer of cement forming a firm mechanical interconnection between the piezoelectric generator I and the header 2. The header 2 has an integrally formed reduced section 2b thereon having a sample socket 2c in the end thereof and having external screw-threads 2d formed on the projecting cylindrical portion thereof. Outwardly projecting sets of coacting spring jaws 2f are encompassed by the tapered sleeve I8 which is internally screw-threaded at one end thereof to engage the external screw threads 2f on header 2. The spring jaws 2d are spaced to permit the entry of rod I9 carrying dilator 28 on the end thereof. Rod I9 fits into socket 2c and is maintained in position by tightening sleeve I8 with respect to screw-threads 2d for clamping spring jaws 2f against the sides of rod I9. Thus, the dilator may be moved over the surface of tissues to positions where the dilaterV 20 may contact gallstones transmitting a force to the header 2 which in turn transmits the force through end portion Ia of the electroacoustical generator I into the electroacoustical generator I, producing by such applied force the generation of electrical potentials causing a current flow across electrodes 'I and 8 through electrical conductors 6.

In Fig. 3 we have shown a schematic circuit diagram of one form of electron tube amplifier and loudspeaker unit which is associated with the probe embodying our invention as heretofore described. In the circuit arrangement shown, a four-stage amplifier is provided including electron tubes 2I, 22, 23 and 24 having an input circuit 25 connected to conductors 6 of the probe and an output circuit 25 connected to the electrical sound reproducing loudspeaker unit 21. The electron tube amplifier stages for tubes 2I and 22 are resistance-capacitance coupled, as represented at 28.A The third stage of amplification embodying tube 23 is resistance-capacitance ri .zcoupledcto the .output :of fthe.. second -stage of am` pliiication las :shown at .29. The :output -of the third stageo'f .amplification embodying fitubex23 has l.aisingletuned circuit therein `.constituted -byxinductancel and capacitance32 forming-a fplate .load :in vorder1to.:l; wer ythe noise output and vimpllove the v:signal-quality. AThe :tuned V circuitA 3 D hasta Que.o`f.25.1and arresonance cf 1.5 kilocycles. v,'1ihe:c.utp1.it ofi tube 23 :is coupled to the input-cf electrcn tube ?2-4 vthroughf Aresistancecapacitarlce .ccupling, .represented at :32. Power ,for operatfingv :theppower vcircuits z of each of the electron ztubesLis-iobtainedzfrom the transformer system 33 :Shaving .vt-primary .winding 3 4, connected t0 :power lcircuit .leads v35, Y extending to ,the conventional a'llfyolt. 60 :cycle domestic power supply circuit. -IIhe acathodes for the several-electron tubes are energized from transformer secondary Winding 3;6 v-,byparallel ycircuit connections extending from terminalsfof ythe secondary -winding 36 to the i-seueral cathodes The plate: potential forthe several tubeszis-obtainedffrom the full-wave rectifier 31 operating through filter circuit ,38 and `the.potentiometercircuit 39. Y j Y.

. ffiuned-circuitw constituted by inductance 3| fandJ capacitance 32 .suppresses audio resonances in the ampliiier and tunes the amplierto .pass audio frequencies which are displaced in the ...audio .frequency spectrum from any audio firel'quencyrto which the probestructure itself may yabe resonant. .Tuned circuit -30 operates A.to peak the :amplifier system so'that it is sensitiveV .to .those ,f frequencies'generated-incident tothe striking l.o fdilator '20A/against .the hard surface of a .-:gallstone By-virtue ofthe highdamping of the yprobe and the tuning of the .amplificationsystem a clicking sound is iproduced `in theelectrivcal s oundireproducer `21 when the .probe dilator 20:15 tapped against `.the .hard :surface .of a -gailvstone ora scratching noiseis produced as the c lilatcr isscraped against the surface of agall- .stone -These sounds are -Very .readily 4distinguished from the soft A-hissing .sound `produced Y'when the probe diiatoris A,slid against ,a tissue.

Thus the .tuning .of the .amplifier system 'by circuit 30 -coacts with thedamping of the .probe `in fthe-construction-.of a successful detector .for lc- ,cating'gallstonea y l The length ofjrcd .Iilmay Abe .increasedas desiredin-applying the principles of our invention v-kidneystone detection. Therodllf9 `need not metallic but may beceramic or bonded ma- -l-terials .such .as .cloth impregnated with plastic '.,material-y having ,good acoustic transmission. Ain-y Vmaterial. forming a good transmitter of ,sound'waves maybe used forv thematerial of rod 19. The 'function of rodi! 9 iscto form a transmittinglmedium for-acoustic Waves to the electro- .acoustic device within the body of the probe.

l ,The .damping of .the electroacoustical generatoris.accomplishedlby the contacting frictional relation kof the parallelopiped or packet forming :.-generator I, .with the interior Wall-of .the housing f3,- .the .edges of vthe ,generator wiping the interior ltubular wall o'f the sheath of insulation materiall.

"The ,"fact 'that "all exposed external `parts of 'theQprobve 'are `metal upermits -the probe 'to 'be "'slteriliaedand --rendered free ofgerms in prepara- Ation 4lfor-each diagnosis. We nhave Vsuccessfully used stainless 'steel for all Vof the metallic yparts o'ftheprobe.

'Throughout the 'specicationf-and claims `-Where 'we have referred 4to Vthe term fgallstones, .it is desired `to '-be vunderstood that this term 4i's to lbe --considered ...asvgembracive cf :any hardisurface vmaterialpr 'foreign' body which may be embedded :adjacentzbody tissue. That .is `to isay, our fmethod and :apparatus is :applicable lnot ,only 'to ftheiiocation `,of gallstones but :also :for the probing. lfof metallic ,bodies such as bullets `or .fragmentsiof fmetal, glass, steel, fetc., lodged wounds, fand fwe vdo notintendthe :term -"ga1istones, to ybe restricted only tothe xterm Aas used .in the `medicalfprorfession.

- While we. have ifound tthe. :structure undici-r.- 'cut arrangement -disclosed fhcrein highlyzpractif.- cal and successful :in operation: we realize that modifications and :changes may ble:.madezand `desire that, it :be #understood that no 'limitations jupon nur invention :are intended `:other athanrmay be imposed by the scope of thesappendedsclaims.

Whatwepclaim as newgandtdesire .to'secure by ILetters Patent in the United @States :isfasgfollcws:

1. jAn electronic apparatus fur Alocating hard bodiesembeddediadiacent'bodytissue comprising `a probeihaving a dilatorfon ,the-end thereof,;a:-i:od `extending therefrom, a fheader connected. with said lrod. a tubular housing-connected :witnsaid header, aheader closing fthe nopposite end-of said housing, :said last mentined header .having 'la lpassage. for,electricalgconductors extending therethrough, .a tpiez,o-electriccrystal element rie-vins .points of vdifiere.nt v.potential y.connected with .said

electrical .conductors and connected. vwith .said iirst mentioned header zand.` an ;-,e 1ect rfic a,lly,ref sponsiye system connected With,s aid.e1ectrical conductors iand responsive tog contact, of said .dilaltorwth hard bodies embedded radjacent body tissue lfor detecting @the presence cf such ,hard -bodies and distinguishing the `hard bodies ,from

adjacent body tissue.

' `a piezo-electric generator having a .linearly .Tex-

Atending portion terminating in abutment lend portions, one of said abutment-end portions, being secured to said rrstnientioned header .andterminal connections secured'adjacent the .othemabut- .ment 'end portion andconnected with points'vlof opposite potential onsaid vzpiezo-electricgenerator, conductors-connected with said terminal connections and leading through `the passageiinsaid last'mentiohed header, an -Velectron tube .ampli- .cation system having input and routput circuits, a connection between-said conductors andsaid input circuit, a sound reproducer in saidloutput circuit and means associated with said circuits for increasing the amplitude of response oflsaid electron tube amplification system to frequencies 'incidental to the establishment of contacts betweenvsaid .dilator and gallstones vembedded l.in adjacent body tissue for. producing an .acoustic response in said sound `reproducer characteristic of the said contacts `with gallstones and distinguishing the contacts -with vgallstones from contacts -with adjacent body tissue.

3. An electronic napparatus for locating foreign bodies embedded adjacent body tissue, comprising `a probe having a `dilater on the end thereof. a rod extending therefrom, a header connected-'With said. rod, Va tubular housing connected `with .said i-header, a'headery closing the opposite'end o'f'said housing, :said last mentioned header' .having a ,7l passage for electrical conductors extending therethrough, a piezoelectric device having an end portion secured to Asaid first mentioned header and-having electrode faces'electrically connected with said electrical Vconductors which extend through the passage in said last mentioned header, an electron Atube amplification system having input and output circuits, connections between said electrical conductors and said input circuit, a sound reproducer, connections between said sound reproducer and said output circuit, and means for sensitizing said electron tube amplification system to frequencies incidental to the contact of said dilator with foreign bodies for distinguishing said foreign bodies from adjacent body tissue and detecting the presence of said foreign bodies.

'4. An electronic apparatus for locating foreign bodies embedded adjacent body tissue, comprising a probe having a dilator on the end thereof, a rod extending therefrom, a header connected with said rod, a tubular housing connected with said header, a header closing the opposite end of said housing, said last mentioned header having a passage for electrical conductors extending therethrough, a piezoelectric device having an end portion secured to said first mentioned header and having electrode faces electrically connected with said electrical conductors Which extend through the passage in said last mentioned header, an electron tube amplification system having input and output circuits, connections between said electrical conductors and said input circuit, a sound reproducer, connections between said sound reproducer and said output circuit, and an audio frequency tunable circuit in said amplifier for adjusting said amplifier for peak response on frequencies incidental to contacts ofV said dilator with foreign bodies embedded adjacent body tissue for detecting the presence of said foreign bodies and distinguishing the'foreign bodies from adjacent body tissue.

5. An electronic apparatus for locating hard bodies embedded adjacent body tissue, comprising a probe having a dilator on the end thereof, a rod extending therefrom,fa header connected with saidrod, a tubular housing connected with said header, a header closing the opposite end of said housing, said last mentioned header having a passage for electrical conductors extending therethrough, a linearly-extendingpiezo-electric device enclosed by said tubular housing and damped for operation therein, said device being connected with said first mentioned header at the end thereof and having electrodes adjacent the opposite end thereof, electrical conduct-ors connected with said electrodes and extending through the passage for the electrical conductors in said second mentioned header, an electron tube amplifier having input and outputY circuits, a sound reproducer connected with said outputcircuit, connections between said'input circuit and said electrical conductors, and means in said electron tube amplifier tuned to pass frequencies displaced from the frequencies characteristics of, and incidental toY a contact established by said dilator with hard bodies embedded adjacent body tissue for detecting the presence'of said hard bodies and distinguishing the hard bodies from adjacent body tissue. Y

6. A probe for detecting hard bodies embedded adjacent body tissue comprising a tubular housing, a header on each'end'of said'housing and forming duid-tight seals with opposite ends of said housing, a chuck formed on one of said headers, a dilator removably mounted in saidchuck and forming a probe for contacting hard bodies embedded in body tissue and constituting a motion transmitting rod for transmitting movements incident to the striking of contacting hard bodies, the other of said headers having an axial passage therethrough, a piezo electric generator disposed within said housing and extending linearly therethrough, said generator having one end fastened to said first mentioned header substantially in alignment with said chuck, electrodes on said generator, electrical conductors connected with said electrodes and extending through the passage in said second mentioned header, and means for sealing said electrical conductors with respect to said second mentioned header adjacent the entry thereof into said housing.

7. A probe for detecting hard bodies embedded in body tissue as set forth in claim 6 in which said generator is damped by contact of the linear edges of said generator with the inside walls of said housing.

8. In a probe for detecting hard bodies embedded in body tissue as set forth in claim 6 in which said generator comprises a stack of ceramic piezoelectric elements connected together in series.

9. In a probe for detecting hard bodies embedded in body tissue as set forth in claim 6 in which said piezo-electric generator comprises a stack of elements extending longitudinally within said housing wherein the transverse dimension of said stack substantially fills said housing and in which the longitudinal dimension of the stack exceeds the dimension of any one of the transverse dimensions thereof.

10. In a probe for detecting hard bodies embedded in body tissue as set forth in claim 6 in which said piezo-electric generator has a longitudinal dimension exceeding its lateral dimension and in which the ends thereof are substantially parallel to each other.

11. An electronic apparatus for locating hard bodies embedded adjacent body tissue comprising an acoustic wave transmitting probe having a dilator on the remote end thereof and an acoustic Wave transmitting rod extending therefrom, a header connected with said rod, a tubular housing connected with said header, another header enclosing the opposite end of said housing, said last mentioned header having an axially extending passage for electrical conductors extending therethrough, an electroacoustic element having electrodes connected with said conductors, said electroacoustic element being connected with said first mentioned header and an electrically responsive system connected with said conductors and responsive to the contact of said dilator with hard bodies embedded in body tissue for detecting the presence of said hard bodies and distinguishing the hard bodies from adjacent body tissue.

12. An electronic apparatus for locating hard bodies embedded adjacent body tissues, comprising a probe having a dilator on the end thereof, a rod extending therefrom, a metallic header connected with said rod, a tubular metallic housing connected with said metallic header, a metallic header closing the opposite end of said metallic housing, said lastmentioned metallic header having an axial passage for electrical conductors extending therethrough, a sleeve of insulation material disposed within said tubular housing and between said metallic headers, an electroacoustic element located within said sleeve of insulation material and insulatingly spaced from said metallic housing and from said last mentioned metallic header, and mechanically connected with said first mentioned metallic header, said electroacoustic element having spaced electrodes thereon, electrical conductors connected with said spaced electrodes and extending through the axial passage in said last mentioned metallic header, and an electrically responsive system connected with said conductors and responsive to the contact of said dilater with hard bodies embedded in body tissue for detecting the presence of said hard bodies and distinguishing the hard bodies from adjacent body tissue.

CHARLES K. KIRBY.

EDWARD G. THURSTON.

ERIC A. WALKER.

l 0 REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS 

